Method for separating paraxylene comprising adsorption with water injection and crystallisation

摘要

A process for separating para-xylene from a C8 feed in a simulated moving bed that comprises a step for adsorption on a zeolite, and desorption using a desorbent, delivering an extract and a raffinate, and an extract crystallization step. A stream of water is introduced into the feed, into the desorbent and/or into the stream for recycling one flux in the column, such that the weighted average of the amounts of water measured in the extract and in the raffinate is in the range 1-200ppm. The ration S/F of the desorbent flow rate to that of the feed during the adsorption and desorption step is in the range of 0.6 to 2.5.